The development platform and tools strategy at Microsoft is getting increasingly complex, especially around XAML/Windows Presentation Foundation (WPF) and Silverlight. Here's the latest.

Microsoft on June 20 split up its XAML team, sending part of it to Windows, part to Windows Phone and leaving part in the Developer Division, according to an e-mail from Developer Division chief Soma Somasegar dated June 20.

Why does this matter? XAML -- the eXtensible Markup Language -- is an XML language developed by Microsoft. From Microsoft's own description page about XAML: "XAML is the language behind the visual presentation of an application that you develop in Microsoft Expression Blend, just as HTML is the language behind the visual presentation of a Web page." XAML is used by WPF and its Silverlight sibling.

Here's the e-mail from Somaseagar, sent to me by a contact requesting confidentiality:

Over the last couple of years, our Client and Mobile team has done a fantastic job of building a number of XAML related technologies that have been a huge value add to the Microsoft client platforms and an instrumental part of delighting our developer customers. The agility and customer focus that the team has demonstrated over the years has been a pleasure to watch.

Today, we are making some organization changes to bring our platform technologies under a single management structure. These changes are centered around three focus areas:

• The team working on XAML technologies for Windows will move to Windows.

• The team working on XAML technologies for Windows Phone, Xbox and browser plugin will move to Windows Phone.

• The Client and Mobile tools teams, including Windows Phone tools and XAML tools, will stay in DevDiv.

These changes are all effective immediately. From a performance review perspective, we will do this year’s performance review underthe DevDiv organization model.

I want to thank Kevin Gallo and the team for all the great work that they have done over the years. Moving forward, I'm very excited to bring the client platform efforts closer to the platform teams. There is a lot of very exciting and critical work underway as part of our next wave of platform releases and I am very eagerly looking forward to seeing the team’s work in the hands of our developers and customers.

The follow-up emails will provide more details on thechanges to those impacted. Please join me in wishing Kevin and the team all the very best as we move forward. If you have any questions about this change, please let your manager or me know.

The "team working on XAML technologies for Windows" referred to in the Somasegar e-mail includes the Jupiter team. If you need a Jupiter refresher, Jupiter is a new UI library for Windows, as of Windows 8, that is expected to be a thinly layered on top of Windows APIs and frameworks for graphics, text, media, input and can be used to build immersive apps using a XAML based approach. Last I heard, Jupiter would allow developers a choice of programming langues. Jupiter-based immersive apps supposedly will be deployed through the Windows App Store.

However, according to another June 20 e-mail from Julie Larson-Green, the Corporate Vice President of Windows Experience on the Windows client team, the part of the XAML team that is going to the Windows team "will continue their work on Windows 8 as planned and will join our Developer Experience (DEVX) team. This transition allows us to bring together our platform development team in a single-management structure."

That seems to be good news for devs not comfy with Microsoft's seeming HTML5/JavaScript force-feed. It sounds as though even if .NET, per se, fades, developers should still be able to code with C#/XAML. (In other words, .NET lives under a new name.)

Kevin Gallo, just a month ago, was referred to in a Microsoft Server and Tools reorg memo as the guy heading up the "Client Platform Team" in the Developer Division, following Scott Guthrie's transition to the Windows Azure team. His Linkedin Profile lists him as the "General Manager of Silverlight." So that means the Silverlight team seems to no longer be in the Developer Division. Does Gallo still have a job at Microsoft? Not clear, but I'm thinking he now works in Windows client (?).

Update: One of my readers says that Gallo was moved to the Windows Phone development team, given that's where the Silverlight plug-in is going

I tried to contact the powers-that-be in Microsoft's Developer Division this week for clarification on the Silverlight/Jupiter/Windows 8 development situation and received no comment (beyond being sent a link to the upcoming Build conference).